/*
 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * This file is built upon the file: src/arch/rtxc/netif/sioslip.c
 *
 * Author: Magnus Ivarsson <magnus.ivarsson(at)volvo.com>
 */

/*
 * This is an arch independent SLIP netif. The specific serial hooks must be
 * provided by another file. They are sio_open, sio_recv and sio_send
 */

#include "netif/slipif.h"
#include "lwip/opt.h"
#include "lwip/def.h"
#include "lwip/pbuf.h"
#include "lwip/sys.h"
#include "lwip/stats.h"
#include "lwip/sio.h"

#define SLIP_END     0300
#define SLIP_ESC     0333
#define SLIP_ESC_END 0334
#define SLIP_ESC_ESC 0335

#define MAX_SIZE     1500

/**
 * Send a pbuf doing the necessary SLIP encapsulation
 *
 * Uses the serial layer's sio_send()
 */
err_t
slipif_output(struct netif *netif, struct pbuf *p, struct ip_addr *ipaddr)
{
        struct pbuf *q;
        u16_t i;
        u8_t c;

        /* Send pbuf out on the serial I/O device. */
        sio_send(SLIP_END, netif->state);

        for (q = p; q != NULL; q = q->next)
        {
                for (i = 0; i < q->len; i++) {
                        c = ((u8_t *)q->payload)[i];
                        switch (c) {
                        case SLIP_END:
                                sio_send(SLIP_ESC, netif->state);
                                sio_send(SLIP_ESC_END, netif->state);
                                break;
                        case SLIP_ESC:
                                sio_send(SLIP_ESC, netif->state);
                                sio_send(SLIP_ESC_ESC, netif->state);
                                break;
                        default:
                                sio_send(c, netif->state);
                                break;
                        }
                }
        }
        sio_send(SLIP_END, netif->state);
        return 0;
}

/**
 * Handle the incoming SLIP stream character by character
 *
 * Poll the serial layer by calling sio_recv()
 *
 * @return The IP packet when SLIP_END is received
 */
static struct pbuf *
                        slipif_input(struct netif *netif)
{
        u8_t c;
        struct pbuf *p, *q;
        u16_t recved;
        u16_t i;

        q = p = NULL;
        recved = i = 0;
        c = 0;

        while (1)
        {
                c = sio_recv(netif->state);
                switch (c) {
                case SLIP_END:
                        if (recved > 0) {
                                /* Received whole packet. */
                                pbuf_realloc(q, recved);

                                LINK_STATS_INC(link.recv);

                                LWIP_DEBUGF(SLIP_DEBUG, ("slipif: Got packet\n"));
                                return q;
                        }
                        break;

                case SLIP_ESC:
                        c = sio_recv(netif->state);
                        switch (c) {
                        case SLIP_ESC_END:
                                c = SLIP_END;
                                break;
                        case SLIP_ESC_ESC:
                                c = SLIP_ESC;
                                break;
                        }
                        /* FALLTHROUGH */

                default:
                        if (p == NULL) {
                                LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: alloc\n"));
                                p = pbuf_alloc(PBUF_LINK, PBUF_POOL_BUFSIZE, PBUF_POOL);

                                if (p == NULL) {
                                        LINK_STATS_INC(link.drop);
                                        LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: no new pbuf! (DROP)\n"));
                                }

                                if (q != NULL) {
                                        pbuf_cat(q, p);
                                } else {
                                        q = p;
                                }
                        }
                        if (p != NULL && recved < MAX_SIZE) {
                                ((u8_t *)p->payload)[i] = c;
                                recved++;
                                i++;
                                if (i >= p->len) {
                                        i = 0;
                                        if (p->next != NULL && p->next->len > 0)
                                                p = p->next;
                                        else
                                                p = NULL;
                                }
                        }
                        break;
                }

        }
        return NULL;
}

/**
 * The SLIP input thread.
 *
 * Feed the IP layer with incoming packets
 */
static void
slipif_loop(void *nf)
{
        struct pbuf *p;
        struct netif *netif = (struct netif *)nf;

        while (1) {
                p = slipif_input(netif);
                netif->input(p, netif);
        }
}

/**
 * SLIP netif initialization
 *
 * Call the arch specific sio_open and remember
 * the opened device in the state field of the netif.
 */
err_t
slipif_init(struct netif *netif)
{

        LWIP_DEBUGF(SLIP_DEBUG, ("slipif_init: netif->num=%"U16_F"\n", (u16_t)netif->num));

        netif->name[0] = 's';
        netif->name[1] = 'l';
        netif->output = slipif_output;
        netif->mtu = 1500;
        netif->flags = NETIF_FLAG_POINTTOPOINT;

        netif->state = sio_open(netif->num);
        if (!netif->state)
                return ERR_IF;

        sys_thread_new(slipif_loop, netif, SLIPIF_THREAD_PRIO);
        return ERR_OK;
}
